Stabilized ubisemiquinone in reconstituted succinate ubiquinone reductase

Yan Xu, J. C. Salerno, Y. H. Wei, Tsoo E. King

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

QP-S, a ubiquinone (Q) protein, accepts electrons from succinate through succinate dehydrogenase (SDH). A new method has produced a preparation of QP-S which has a different amino acid composition and SDS gel electrophoretic pattern from that of the old preparation (Biochemistry 19, 3579-3585 (1980)). The new preparation contains less than 1 nmol heme/mg protein; the activity of the preparation was not proportional to its heme content. A thenoyltrifluoroacetone sensitive free radical signal was detected by EPR spectroscopy in succinate-Q reductase reconstituted from this QP-S and SDH; the characteristics of this species identify it as ubisemiquinone. At pH 7.4, the Em of the two electron step was about 70 mV with E1 = 5 mV and E2 = 125 mV. The properties of the radical differed slightly from those of "Qs" radical in more intact preparations (e.g. submitochondrial particles). The present is the simplest system in which such a succinate reducible ubisemiquinone free radical has been demonstrated.

Original languageEnglish (US)
Pages (from-to)315-322
Number of pages8
JournalBiochemical and Biophysical Research Communications
Volume144
Issue number1
DOIs
StatePublished - Apr 14 1987
Externally publishedYes

Fingerprint

coenzyme Q10
Electron Transport Complex II
Succinic Acid
Succinate Dehydrogenase
Free Radicals
Thenoyltrifluoroacetone
Submitochondrial Particles
Electrons
Biochemistry
Ubiquinone
Heme
Paramagnetic resonance
Spectrum Analysis
Oxidoreductases
Proteins
Gels
Spectroscopy
Amino Acids
Chemical analysis

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

Stabilized ubisemiquinone in reconstituted succinate ubiquinone reductase. / Xu, Yan; Salerno, J. C.; Wei, Y. H.; King, Tsoo E.

In: Biochemical and Biophysical Research Communications, Vol. 144, No. 1, 14.04.1987, p. 315-322.

Research output: Contribution to journalArticle

Xu, Yan ; Salerno, J. C. ; Wei, Y. H. ; King, Tsoo E. / Stabilized ubisemiquinone in reconstituted succinate ubiquinone reductase. In: Biochemical and Biophysical Research Communications. 1987 ; Vol. 144, No. 1. pp. 315-322.
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